SUMMARY
The default "file type" for *.log files is and will always be: (general, unspecified) log file.  In most cases, these are text files, thus the correct file association is "text/x-log".  The extension *.out is e.g. by default used by the compiler (the famous "a.out" file), and is generally used to store any (thus unspecified) kind of output into a file.  These two extensions should be general and not be specific.

STEPS TO REPRODUCE
1. Enable "open in embedded viewer" for text files, e.g. in konqueror.
2. Open a folder that contains *.log files in konqueror
3. Klick on a *.log file

OBSERVED RESULT
The file is opened with kate (default for "chemical/x-gaussian-log")

EXPECTED RESULT
The file should be opened in the embedded text viewer

SOFTWARE/OS VERSIONS
FreeBSD: 14.3-RELEASE-p5
Windows: 
macOS: 
(available in the Info Center app, or by running `kinfo` in a terminal window)
Linux/KDE Plasma: 
KDE Plasma Version: 6.4.5
KDE Frameworks Version: 6.18.0
Qt Version: 6.9.3

ADDITIONAL INFORMATION
The real error is that the one who did this does not use a clean environment to produce distribution files.  One can change the association of *.log files in one's private environment, but these changes must never change the sane defaults for files that go into a software distribution.